package com.ecobell.camera;

import java.io.IOException;
import java.util.List;

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class Preview extends SurfaceView implements SurfaceHolder.Callback {
	private static final String TAG = Preview.class.getSimpleName();
	
	SurfaceHolder mHolder;
    Camera mCamera;
	
	public Preview(Context context) {
		super(context);
		// 
		mHolder = getHolder();
		mHolder.addCallback(this);
		mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
	}

	@Override
	public void surfaceChanged(SurfaceHolder holder, int format, int width,
			int height) {
		// Now that the size is known, set up the camera parameters and begin
        // the GeneralPreview.
        Camera.Parameters parameters = mCamera.getParameters();

        List<Size> sizes = parameters.getSupportedPreviewSizes();
        Size optimalSize = getOptimalGeneralPreviewSize(sizes, width, height);
        parameters.setPreviewSize(optimalSize.width, optimalSize.height);

        mCamera.setParameters(parameters);
        mCamera.startPreview();
        
	}

	@Override
	public void surfaceCreated(SurfaceHolder holder) {
		mCamera = Camera.open();
        try {
           mCamera.setPreviewDisplay(holder);
        } catch (IOException e) {
        	mCamera.release();
            mCamera = null;
		}
	}

	@Override
	public void surfaceDestroyed(SurfaceHolder holder) {
		mCamera.stopPreview();
        mCamera.release();
        mCamera = null;
	}

	private Size getOptimalGeneralPreviewSize(List<Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.05;
        double targetRatio = (double) w / h;
        if (sizes == null) return null;

        Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = h;

        // Try to find an size match aspect ratio and size
        for (Size size : sizes) {
            double ratio = (double) size.width / size.height;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }

        // Cannot find the one match the aspect ratio, ignore the requirement
        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }
        return optimalSize;
    }
}
